A wide variety of IMDs that deliver a therapy to or monitor a physiologic condition of a patient have been clinically implanted or proposed for clinical implantation in patients. In some instances, an IMD may provide the capability to monitor a physiological condition of a patient, such as pressure, electrocardiogram (ECG), oxygen level or the like. In such cases, the IMD may or may not provide therapy to the patient. If therapy is delivered to the patient in addition to monitoring the physiological condition, the IMD may include a therapy module that delivers therapy to any of a variety of organs, nerves, muscles or tissues of the patients, such as the heart, brain, stomach, spinal cord, pelvic floor, or the like.
For example, an IMD may deliver electrical stimulation therapy via one or more electrodes, which may be included as part of one or more elongated implantable medical leads. An implantable cardiac device, such as a cardiac pacemaker or implantable cardioverter-defibrillator, provides therapeutic electrical stimulation to the heart by delivering electrical therapy signals such as pulses or shocks for pacing, cardiac resynchronization, cardioversion, or defibrillation via the one or more electrodes. As another example, a neurostimulator may deliver electrical therapy signals, such as pulses, to a spinal cord, brain, pelvic floor or the like to alleviate pain or treat symptoms of any of a number of neurological or other diseases, such as epilepsy, gastroparesis, Alzheimer's, depression, obesity, incontinence and the like.
The IMD may also deliver other therapy, such as drug therapy, in addition to or instead of electrical stimulation therapy. For example, the IMD may deliver a drug or other therapeutic agent to the patient to treat pain or other symptoms of the condition of the patient. For example, the IMD may deliver morphine to an intrathecal location to treat pain. As another example, the IMD may deliver chemotherapy for the treatment of cancer. An IMD that delivers a drug or other therapeutic agent may sometimes be referred to as a drug pump or drug delivery device. In some instances, a fluid other than a drug may be delivered to a location within a patient.
The IMD may include a telemetry module that may exchange communications with a programming device (sometimes referred to as a programmer) or a monitoring device. For example, the IMD may transmit information related to a condition of a patient, such as physiological signals measured by one or more sensors, or information related to a therapy delivered to the patient, to the programming device or monitoring device. The IMD may also receive information from the programming device or the monitoring device, such as configuration information that may be used to configure a therapy to be provided to the patient.
The various components of the IMDs, including sensing components, therapy delivery components and/or telemetry components, receive power from a power source. The power source may have a limited service life that may vary greatly based on the type of therapy provided to the patient. The service life of the power sources, which in some instances may be a non-rechargeable battery, is typically on the order of several to tens of years.